1. Field of the Invention
The present invention pertains to guidewires for use with intravascular catheters. More particularly, the present invention pertains to guidewires with an improved, atraumatic distal tip.
2. Description of the Related Art
The use of intravascular catheters has become an effective method for treating many types of vascular disease. In general, an intravascular catheter is inserted into the vascular system of the patient and navigated through the vasculature to a desired target site. Using this method, virtually any target site in the patient""s vascular system may be accessed, including the coronary, cerebral, and peripheral vasculature. Examples of therapeutic purposes for intravascular catheters include percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA).
Intravascular catheters are commonly used in conjunction with a guidewire. A guidewire may be advanced through the patient""s vasculature until it has reached a target location. Once in place, a catheter may be threaded onto the guidewire and urged distally until the distal end of the catheter reaches a target location.
The vasculature of a human being can be a very tortuous path. In order for a guidewire to be steered through the vasculature, it may be beneficial for the guidewire to be flexible, particularly near the distal end. Increased flexibility may be incorporated into a guidewire in a number of differing ways. For example, the distal tip of the guidewire may be tapered.
A coil may be disposed about the guidewire, for example to provide support and/or strength. It may be desirable for the coil to be secured to the guidewire. This may be accomplished by welding a portion of the coil to the inner core member of the guidewire. Welding may require the use of a heat sink to help absorb some of the heat generated during welding. Following welding, the heat sink may be removed by grinding. Grinding may also serve to smooth the distal tip.
The present invention pertains to a refinement of guidewires. More particularly, the present invention pertains to guidewires with an improved distal tip. The distal tip may include an atraumatic solder tip. The atraumatic tip may help to secure a coil to the inner shaft of the guidewire. Moreover, the atraumatic tip may be formed by performing a minimal amount of processing steps.
The guidewire may include an inner elongate shaft having a coil disposed along at least a portion of its length. A solder ball may be disposed at the distal end of the shaft and a quantity of flux may be disposed proximate the solder ball. A heat source may be disposed proximate the solder ball for heating the solder ball to a temperature where at least a portion of the solder ball may be melted. Heating the solder ball may activate the flux and result in flow of molten solder proximally. Solder remaining at the distal end of the shaft may form the atraumatic distal tip. A holding fixture may be coupled to the shaft that may comprise a heat sink to draw away or absorb heat. A heat shrink tube may also be coupled to the shaft to stop proximal migration of flux and/or solder.